Online purchase missing items

I purchased three items online when the store had cyber Monday. I only received 2 of the 3 items yet the invoice has all three items meaning the delivery has not been split. I went to the store in Fourways to query and they told me they can’t help me I must call the store the items were dispatched from. I made countless calls to the store in Somerset Mall and only got a hold of them earlier today (03/12) the agent said they would call me back around 11:15 and they still haven’t. When I tried to call the store again they did not pick up. I’m very disappointed in the services, I want my item of they must refund my money back for everything.